Surface activation and targeting strategies of superparamagnetic iron oxide nanoparticles in cancer-oriented diagnosis and therapy

Targeted Rapamycin Delivery via Magnetic Nanoparticles to Address Stenosis in a 3D Bioprinted in Vitro Model of Pulmonary Veins

Vascular cell overgrowth and lumen size reduction in pulmonary vein stenosis (PVS) can result in elevated PV pressure, pulmonary hypertension, cardiac failure, and death. Administration of chemotherapies such as rapamycin have shown promise by inhibiting the vascular cell proliferation; yet clinical success is limited due to complications such as restenosis and off-target effects. The lack of in vitro models to recapitulate the complex pathophysiology of PVS has hindered the identification of disease mechanisms and therapies. This study integrated 3D bioprinting, functional nanoparticles, and perfusion bioreactors to develop a novel in vitro model of PVS. Bioprinted bifurcated PV constructs are seeded with endothelial cells (ECs) and perfused, demonstrating the formation of a uniform and viable endothelium. Computational modeling identified the bifurcation point at high risk of EC overgrowth. Application of an external magnetic field enabled targeting of the rapamycin-loaded superparamagnetic iron oxide nanoparticles at the bifurcation site, leading to a significant reduction in EC proliferation with no adverse side effects. These results establish a 3D bioprinted in vitro model to study PV homeostasis and diseases, offering the potential for increased throughput, tunability, and patient specificity, to test new or more effective therapies for PVS and other vascular diseases.

Cetuximab-conjugated chitosan-pectinate (modified) composite nanoparticles for targeting colon cancer

In the present study, we successfully developed a cetuximab-conjugated modified citrus pectin-chitosan nanoparticles for targeted delivery of curcumin (Cet-MCPCNPs) for the treatment of colorectal cancer. In vitro analyses revealed that nanoparticles were spherical with size of 249.33 ± 5.15 nm, a decent encapsulation efficiency (68.43 ± 2.4%) and a 'smart' drug release profile. 61.37 ± 0.70% of cetuximab was adsorbed to the surface of the nanoparticles. Cellular uptake studies displayed enhanced internalization of Cet-MCPCNPs in Caco-2 (EGFR +ve) cells, which ultimately resulted in a significant reduction in cancer cell propagation. The cell cycle analysis indicated that Cet- MCPCNPs induced cell death in enhanced percentage of Caco-2 cells by undergoing cell cycle arrest in the G2/M phase. These data suggest that Cet-MCPCNPs represent a new and promising targeting approach for the treatment of colorectal cancer.

Multipronged design of theranostic nanovehicles with endogenous and exogenous stimuli-responsiveness for precise cancer therapy

Near-infrared (NIR) light-induced photothermal agent-based stimuli-responsive materials have attracted great interest from researchers. However, the highly smart release with precise control by NIR light is not yet well established because of the lack or inadequacy of intelligent release systems, such as premature release of drug and/or photothermal agent. Herein, we put forward a novel and convenient strategy to synthesize cyanine dye-functionalized polymeric materials, where cyanine dye was schemed to attach to polymeric materials by copolymerization, endowing the polymeric materials with NIR light-responsive photothermal property and fluorescent nature for real-time imaging of endocytosis and intracellular trafficking of nanovehicles. Meanwhile, the chemotherapy drug DOX was introduced into the cyanine-containing polymeric materials via formation of dynamic covalent hydrazone bond to circumvent the blood circulation barrier. The nanovehicles displayed fine pH/NIR light-controlled drug release and excellent tumor intracellular drug transposition, which were ulteriorly combined with photo-triggered hyperthermia for enhanced antitumor effect. Therefore, this multipronged design of theranostic nanovehicles with endogenous and exogenous stimuli-responsiveness provides a novel strategy to attain highly smart drug delivery for precise cancer therapy.

Functional Built-In Template Directed Siliceous Fluorescent Supramolecular Vesicles as Diagnostics

Functional template directed synthesis of hybrid siliceous fluorescent vesicle (HSFV) is fabricated by using fluorescent vesicle as a built-in template. The template vesicle is the ionic self-assembly of an aggregation-induced emission (AIE) fluorogen. Upon depositing folic acid modified silica shell on its surface, the obtained HSFVs display low cytotoxicity, significant fluorescence, and targeted drug delivery toward cancer cells. Furthermore, the wall-thickness of the HSFVs can be controlled via altered concentration of silica source. This is the first report of HSFV employing the template vesicle as a built-in fluorescent agent, which represents a good example of rational design for an effective diagnostics, and may open up a new avenue for precision medicine.

Charge-Convertible Carbon Dots for Imaging-Guided Drug Delivery with Enhanced in Vivo Cancer Therapeutic Efficiency

Carbon dots (CDs) are remarkable nanocarriers due to their promising optical and biocompatible capabilities. However, their practical applicability in cancer therapeutics is limited by their insensitive surface properties to complicated tumor microenvironment in vivo. Herein, a tumor extracellular microenvironment-responsive drug nanocarrier based on cisplatin(IV) prodrug-loaded charge-convertible CDs (CDs-Pt(IV)@PEG-(PAH/DMMA)) was developed for imaging-guided drug delivery. An anionic polymer with dimethylmaleic acid (PEG-(PAH/DMMA)) on the fabricated CDs-Pt(IV)@PEG-(PAH/DMMA) could undergo intriguing charge conversion to a cationic polymer in mildly acidic tumor extracellular microenvironment (pH ∼ 6.8), leading to strong electrostatic repulsion and release of positive CDs-Pt(IV). Importantly, positively charged nanocarrier displays high affinity to negatively charged cancer cell membrane, which results in enhanced internalization and effective activation of cisplatin(IV) prodrug in the reductive cytosol. The in vitro experimental results confirmed that this promising charge-convertible nanocarrier possesses better therapeutic efficiency under tumor extracellular microenvironment than normal physiological condition and noncharge-convertible nanocarrier. The in vivo experiments further demonstrated high tumor-inhibition efficacy and low side effects of the charge-convertible CDs, proving its capability as a smart drug nanocarrier with enhanced therapeutic effects. The present work provides a strategy to promote potential clinical application of CDs in the cancer treatment.

Stable, polymer-directed and SPION-nucleated magnetic amphiphilic block copolymer nanoprecipitates with readily reversible assembly in magnetic fields

The formation of inorganic-organic magnetic nanocomposites using reactive chemistry often leads to a loss of super-paramagnetisim when conducted in the presence of iron oxide nanoparticles. We present here a low energy and chemically-mild process of co-nanoprecipitation using SPIONs and homopolymers or amphiphilic block copolymers, of varying architecture and hydrophilic/hydrophobic balance, which efficiently generates near monodisperse SPION-containing polymer nanoparticles with complete retention of magnetism, and highly reversible aggregation and redispersion behaviour. When linear and branched block copolymers with inherent water-solubility are used, a SPION-directed nanoprecipitation mechanism appears to dominate the nanoparticle formation presenting new opportunities for tailoring and scaling highly functional systems for a range of applications.

Multimodal iron oxide (Fe3O4)-saturated lactoferrin nanocapsules as nanotheranostics for real-time imaging and breast cancer therapy of claudin-low, triple-negative (ER-/PR-/HER2-)

Aim: To unravel the multimodal nanotheranostic ability of Fe3O4-saturated bovine lactoferrin nanocapsules (FebLf NCs) in claudin-low, triple-negative breast cancer model. Materials & methods: Xenograft study was performed to examine biocompatibility, antitumor efficacy and multimodal nanotheranostic action in combination with near-infrared live mice imaging. Results: FebLf NCs exhibited a size range of 80 nm ± 5 nm with observed superparamagnetism. FebLf NCs successfully internalized into breast cancer cells through receptor-mediated endocytosis and induced apoptosis through the downregulation of inhibitor of apoptosis survivin and livin proteins. Investigations revealed a remarkable biocompatibility, anticancer efficacy of the FebLf NCs. Near-infrared imaging observations confirmed selective localization of multimodal FebLf NCs at the tumor site and lead to time-dependent reduction of tumor growth. Conclusion: FebLf NCs can be safe, biocompatible nanotheranostic approach for real-time imaging and monitoring the effect of drugs in real time and have potentials in future clinical trials.

Cellular uptake and biocompatibility of bismuth ferrite harmonic advanced nanoparticles

Bismuth Ferrite (BFO) nanoparticles (BFO-NP) display interesting optical (nonlinear response) and magnetic properties which make them amenable for bio-oriented diagnostic applications as intra- and extra membrane contrast agents. Due to the relatively recent availability of this material in well dispersed nanometric form, its biocompatibility was not known to date. In this study, we present a thorough assessment of the effects of in vitro exposure of human adenocarcinoma (A549), lung squamous carcinoma (NCI-H520), and acute monocytic leukemia (THP-1) cell lines to uncoated and poly(ethylene glycol)-coated BFO-NP in the form of cytotoxicity, haemolytic response and biocompatibility. Our results support the attractiveness of the functional-BFO towards biomedical applications focused on advanced diagnostic imaging.

FROM THE CLINICAL EDITOR

Bismuth Ferrite nanoparticles (BFO-NP) have been recently successfully introduced as photodynamic tools and imaging probes. However, how these nanoparticles interact with various cells at the cellular level remains poorly understood. In this study, the authors performed in vitro experiments to assess the effects of uncoated and PEG-coated BFO-NP in the form of cytotoxicity, haemolytic response and biocompatibility.

Alkylphosphocholine analogs for broad-spectrum cancer imaging and therapy

Many solid tumors contain an overabundance of phospholipid ethers relative to normal cells. Capitalizing on this difference, we created cancer-targeted alkylphosphocholine (APC) analogs through structure-activity analyses. Depending on the iodine isotope used, radioiodinated APC analog CLR1404 was used as either a positron emission tomography (PET) imaging ((124)I) or molecular radiotherapeutic ((131)I) agent. CLR1404 analogs displayed prolonged tumor-selective retention in 55 in vivo rodent and human cancer and cancer stem cell models. (131)I-CLR1404 also displayed efficacy (tumor growth suppression and survival extension) in a wide range of human tumor xenograft models. Human PET/CT (computed tomography) and SPECT (single-photon emission computed tomography)/CT imaging in advanced-cancer patients with (124)I-CLR1404 or (131)I-CLR1404, respectively, demonstrated selective uptake and prolonged retention in both primary and metastatic malignant tumors. Combined application of these chemically identical APC-based radioisosteres will enable personalized dual modality cancer therapy of using molecular (124)I-CLR1404 tumor imaging for planning (131)I-CLR1404 therapy.

Evaluation of multilayer coated magnetic nanoparticles as biocompatible curcumin delivery platforms for breast cancer treatment

A novel biocompatible multi-layer iron oxide magnetic nanoparticles with sustained sensitive release profile, and improved cellular uptake.

Nanoparticle strategies for cancer therapeutics: Nucleic acids, polyamines, bovine serum amine oxidase and iron oxide nanoparticles (Review)

Nanotechnology for cancer gene therapy is an emerging field. Nucleic acids, polyamine analogues and cytotoxic products of polyamine oxidation, generated in situ by an enzyme-catalyzed reaction, can be developed for nanotechnology-based cancer therapeutics with reduced systemic toxicity and improved therapeutic efficacy. Nucleic acid-based gene therapy approaches depend on the compaction of DNA/RNA to nanoparticles and polyamine analogues are excellent agents for the condensation of nucleic acids to nanoparticles. Polyamines and amine oxidases are found in higher levels in tumours compared to that of normal tissues. Therefore, the metabolism of polyamines spermidine and spermine, and their diamine precursor, putrescine, can be targets for antineoplastic therapy since these naturally occurring alkylamines are essential for normal mammalian cell growth. Intracellular polyamine concentrations are maintained at a cell type-specific set point through the coordinated and highly regulated interplay between biosynthesis, transport, and catabolism. In particular, polyamine catabolism involves copper-containing amine oxidases. Several studies showed an important role of these enzymes in developmental and disease-related processes in animals through the control of polyamine homeostasis in response to normal cellular signals, drug treatment, and environmental and/or cellular stress. The production of toxic aldehydes and reactive oxygen species (ROS), H2O2 in particular, by these oxidases suggests a mechanism by which amine oxidases can be exploited as antineoplastic drug targets. The combination of bovine serum amine oxidase (BSAO) and polyamines prevents tumour growth, particularly well if the enzyme has been conjugated with a biocompatible hydrogel polymer. The findings described herein suggest that enzymatically formed cytotoxic agents activate stress signal transduction pathways, leading to apoptotic cell death. Consequently, superparamagnetic nanoparticles or other advanced nanosystem based on directed nucleic acid assemblies, polyamine-induced DNA condensation, and bovine serum amine oxidase may be proposed for futuristic anticancer therapy utilizing nucleic acids, polyamines and BSAO. BSAO based nanoparticles can be employed for the generation of cytotoxic polyamine metabolites.

Luminescent mesoporous nanoreservoirs for the effective loading and intracellular delivery of therapeutic drugs

Development of biocompatible and multifunctional nanocarriers is important for the therapeutic efficacy of drug molecules in the treatment of disease and tissue repair. A novel nanocarrier of luminescent hollowed mesoporous silica (L-hMS) was explored for the loading and controlled delivery of drugs. For the synthesis of L-hMS, self-activated luminescence hydroxyapatite (LHA) was used as a template. Different thicknesses (∼ 7-62 nm) of mesoporous silica shell were obtained by varying the volume of silica precursor and the subsequent removal of the LHA core, which resulted in hollow-cored (size of ∼ 40 nm × 10 nm) mesoporous silica nanoreservoirs, L-hMS. While the silica shell provided a highly mesoporous structure, enabling an effective loading of drug molecules, the luminescent property of LHA was also well preserved in both the silica-shelled and the hollow-cored nanocarriers. Doxorubicin (DOX), used as a model drug, was shown to be effectively loaded onto the mesopore structure and within the hollow space of the nanoreservoir. The DOX release was fairly pH-dependent, occurring more rapidly at pH 5.3 than at pH 7.4, and a long-term sustainable delivery over the test period of 2weeks was observed. The nanoreservoir exhibited favorable cell compatibility with low cytotoxicity and excellent cell uptake efficiency (over 90%). Treatment of HeLa cells with DOX-loaded L-hMS elicited a sufficient degree of biological efficacy of DOX, as confirmed in the DOX-induced apoptotic behaviors, including stimulation in caspase-3 expression, and was even more effective than the direct DOX treatment. Overall, the newly developed L-hMS nanoreservoirs may be potentially useful as a multifunctional (luminescent, mesoporous and biocompatible) carrier system to effectively load and sustainably deliver small molecules, including anticancer drugs.

Boronate ester bond-based core–shell nanocarriers with pH response for anticancer drug delivery

Currently, the major challenge for cancer treatment is to develop simple and smart nanocarriers that can efficiently retain the encapsulated drug during blood circulation, recognize tumor cells and quickly release the drug under stimulation.

Nonpolymeric surface-coated iron oxide nanoparticles for in vivo molecular imaging: biodegradation, biocompatibility, and multiplatform

A new approach to the surface engineering of superparamagnetic iron oxide nanoparticles (SPIONs) may encourage their development for clinical use. In this study, we demonstrated that nonpolymeric surface modification of SPIONs has the potential to be an advanced biocompatible contrast agent for biomedical applications, including diagnostic imaging in vivo.

METHODS

Adenosine triphosphate (ATP), which is an innate biomaterial derived from the body, was coated onto the surface of SPIONs. An in vivo degradation study of ATP-coated SPIONs (ATP@SPIONs) was performed for 28 d. To diminish phagocytosis, ATP@SPIONs were surface-modified with gluconic acid. We next studied the ability of the SPIONs to serve as a specific targeted contrast agent after conjugation of cMet-binding peptide. The SPIONs were conjugated with Cy5.5 and labeled with (125)I for multimodality imaging. In vivo and in vitro tumor-targeted binding studies were performed on U87MG cells or a U87MG tumor model using animal SPECT/CT, an optical imaging system, and a 1.5-T clinical MR scanner.

RESULTS

ATP@SPIONs showed rapid degradation in vivo and in vitro, compared with ferumoxides. ATP@SPIONs modified with gluconic acid reduced phagocytic uptake, showed improved biodistribution, and provided good targetability in vivo. The gluconic acid-conjugated ATP@SPIONs, when conjugated with cMet-binding peptide, were successfully visualized on the U87MG tumors implanted in mice via multimodality imaging.

CONCLUSION

We suggest that ATP@SPIONs can be used as a multiplatform to target a region of interest in molecular imaging. When we consider the biocompatibility of contrast agents in vivo, ATP@SPIONs are superior to polymeric surface-modified SPIONs.

Near-infrared light-mediated nanoplatforms for cancer thermo-chemotherapy and optical imaging

While thermo-chemotherapy has proved to be effective in optimizing the efficacies of cancer treatments, traditional chemotherapy is subject to adverse side effects and heat delivery is often challenging in operation. Some photothermal inorganic nanoparticles responsive to near infrared light provide new opportunities for simultaneous and targeted delivery of heat and chemotherapeutics to the tumor sites in pursuit of synergistic effects for efficacy enhancement. The state of the art of nanoparticle-induced thermo-chemotherapy is summarized and the advantages and challenges of the major nanoplatforms based on gold nanoparticles, carbon nanomaterials, palladium nanosheets, and copper-based nanocrystals are highlighted. In addition, the optical-imaging potentials of the nanoplatforms that may endow them with imaging-guided therapy and therapeutic-result-monitoring capabilities are also briefly discussed.

Emerging inorganic nanomaterials for pancreatic cancer diagnosis and treatment

Pancreatic cancer is a devastating disease with incidence increasing at an alarming rate and survival not improved substantially during the past three decades. Although enormous efforts have been made in early detection and comprehensive treatment for this disease, little or no survival improvement was obtained, which necessitates the development of novel strategies. Emerging inorganic nanomaterials, such as carbon nanotubes, quantum dots, mesoporous silica/gold/supermagnetic nanoparticles, have been widely used in biomedical research with great optimism for cancer diagnosis and therapy. Such nanoparticles possess unique optical, electrical, magnetic and/or electrochemical properties. With such properties along with their impressive nano-size, these particles can be targeted to cancer cells, tissues, and ligands efficiently and monitored with extreme precision in real-time. In additional to liposome, dendrimer, and polymeric nanoparticles, they are considered the most promising nanomaterials with the capability of both cancer detection and multimodality treatment. Emerging approaches to harness nanotechnology to optimize the existing diagnostic and therapeutic tools for pancreatic cancer have been extensively explored during the recent years. Future options for early detection, individual therapy and monitoring responses of pancreatic cancer are focused on multifunctional nanomedicine. In this review, we present the recent development of clinically applicable inorganic nanoparticles, with focus on the diagnosis and treatment of pancreatic cancer. Furthermore, their advantages in theranostic nanomedicine, and challenges of translation to clinical practice, are discussed.

Multifunctional hollow mesoporous silica nanocages for cancer cell detection and the combined chemotherapy and photodynamic therapy

Highly uniform and multifunctional hollow mesoporous silica nanocages that combined excellent properties (good biocompatibility, fluorescence imaging, drug delivery, and dual-mode cancer therapy) in one single system were synthesized. Dye molecules labeled in the nanocages could be used as traceable detectors in fluorescence imaging. A chemotherapeutic drug, doxorubicin (DOX), has been loaded into the nanocages with a high storage capacity due to the large cubic cavities and could be released through the penetrating mesoporous channels in a sustained fashion. Hematoporphyrin molecules were also covalently doped in the nanocages and allowed for photodynamic therapy. More importantly, a cooperative, synergistic therapy combining chemotherapy and photodynamic therapy exhibited high therapeutic efficacy for cancer therapy in vitro.

Molecular magnetic resonance contrast agents for the detection of cancer: past and present

Magnetic resonance imaging (MRI) is a powerful diagnostic tool with unsurpassed spatial resolution that is capable of providing detailed information about the structure and composition of tumors. The use of exogenously administered contrast agents allows compartment-specific enhancement of tumors, enabling imaging of functional blood and interstitial volumes. Current efforts are directed at enhancing the capabilities of MRI in oncology by adding contrast agents with molecular specificities to the growing armamentarium of diagnostic probes that produce signal by changing local proton relaxation times as a consequence of specific contrast agent binding to cell surface receptors or extracellular matrix components. We review herein the most notable examples, illustrating major trends in the development of specific probes for high-resolution imaging in molecular oncology.

Superparamagnetic nanosystems based on iron oxide nanoparticles for biomedical imaging

Magnetic iron oxide nanoparticles and their dispersion in various mediums are of wide interest for their biomedical applications and physicochemical properties. MFe2O4 or MOFe2O3 (where M = Co, Li, Ni or Mn, for example) can be molecularly engineered to provide a wide range of magnetic properties. In this article, we survey the literature, integrating the results of our work to give a rational view on the synthesis, physicochemical properties and applications of MFe2O4, especially for MRI. However, retrieving detailed biological information on a subcellular level is difficult, owing to the limited resolution and low sensitivity of the MRI technique. Thus, this article also concentrates on the development of a magnetic iron oxide nanoparticles/quantum dot hybrids, as a dual-mode magnetic-fluorescent probe. The synthesis and physicochemical properties of the magnetic iron oxide nanoparticles/quantum dot hybrids and, especially, its application as an MRI-fluorescent probe, will also be described.

Endosome-escapable magnetic poly(amino acid) nanoparticles for cancer diagnosis and therapy

Endosome-escapable poly(amino acid) nanoparticles composed of iron oxide nanocrystals and anticancer drugs were prepared and demonstrated high T(2) relaxivity coefficients and higher efficacy attributed to the endosomolytic ability of the conjugated histidine moiety.

Interaction of cationic ultrasmall superparamagnetic iron oxide nanoparticles with human melanoma cells

Ultrasmall superparamagnetic iron oxide nanoparticles (USPIONs) are currently under development for the intracellular delivery of therapeutics. However, the mechanisms of cellular uptake and the cellular reaction to this uptake, independent of therapeutics, are not well defined. The interactions of biocompatible cationic aminoUSPIONs with human cells was studied in 2D and 3D cultures using biochemical and electron microscopy techniques. AminoUSPIONs were internalized by human melanoma cells in 2D and 3D cultures. Uptake was clathrin mediated and the particles localized in lysosomes, inducing activation of the lysosomal cathepsin D and decreasing the expression of the transferrin receptor in human melanoma cells and/or skin fibroblasts. AminoUSPIONs deeply invaded 3D spheroids of human melanoma cells. Thus, aminoUSPIONs can invade tumors and their uptake by human cells induces cell reaction.

Spectroscopic study of maghemite nanoparticles surface-grafted with DMSA

Nanosized maghemite (below 10 nm average diameter), surface-functionalized with meso-2,3-dimercaptosuccinic acid (DMSA), was investigated with respect to the content of DMSA molecules attached onto its surface and the onset of S-S bridges due to oxidation of neighboring S-H groups. To support our investigation, we introduced the use of photoacoustic spectroscopy to monitor thiol groups (S-H) conjugated with Raman spectroscopy to monitor the disulfide bridges (S-S). The normalized intensity (N(R)) of the Raman feature peaking at 500 cm(-1) was used to probe the S-S bridge whereas the normalized intensity (N(P)) of the photoacoustic band-S (0.42-0.65 μm) was used to probe the S-H moiety. The perfect linearity observed in the N(R) versus (1 - N(P)) plot strongly supports the oxidation process involving neighboring S-H groups as the DMSA surface grafting coefficient increases whereas the approach used in this report allows the evaluation of the [S-H]/[S-S] ratio. The observation of the reduction of the hydrodynamic diameter as the nominal DMSA-grafting increases supports the proposed model picture, in which the intraparticle (interparticle) S-S bridging takes place at higher (lower) DMSA-grafting values.

Assessing iron oxide nanoparticle toxicity in vitro: current status and future prospects

The in vitro labeling of stem or therapeutic cells with engineered nanoparticles with the aim of transplanting these cells into live animals and, for example, noninvasively monitoring their migration, is a hot topic in nanomedicine research. It is of crucial importance that cell–nanoparticle interactions are studied in depth in order to exclude any negative effects of the cell labeling procedure. To date, many disparate results can be found in the literature regarding nanoparticle toxicity due to the great versatility of different parameters investigated. In the present work, an overview is presented of different types of nanomaterials, focusing mostly on iron oxide nanoparticles, developed for biomedical research. The difficulties in assessing nanoparticle-mediated toxicity are discussed, an overview of some of the problems encountered using commercial (dextran-coated) iron oxide nanoparticles is presented, several key parameters are highlighted and novel methods suggested – emphasizing the importance of intracellular nanoparticle degradation and linking toxicity data to functional (i.e., cell-associated) nanoparticle levels, which could help to advance any progress in this highly important research topic.

Iron oxide-based nanomagnets in nanomedicine: fabrication and applications

Iron oxide-based nanomagnets have attracted a great deal of attention in nanomedicine over the past decade. Down to the nanoscale, superparamagnetic iron oxide nanoparticles can only be magnetized in the presence of an external magnetic field, which makes them capable of forming stable colloids in a physio-biological medium. Their superparamagnetic property, together with other intrinsic properties, such as low cytotoxicity, colloidal stability, and bioactive molecule conjugation capability, makes such nanomagnets ideal in both in-vitro and in-vivo biomedical applications. In this review, a chemical, physical, and biological synthetic approach to prepare iron oxide-based nanomagnets with different physicochemical properties was illustrated and compared. The growing interest in iron oxide-based nanomagnets with multifunctionalities was explored in cancer diagnostics and treatment, focusing on their combined roles in a magnetic resonance contrast agent, hyperthermia, and magnetic force assisted drug delivery. Iron oxides as magnetic carriers in gene therapy were reviewed with a focus on the sophisticated design and construction of magnetic vectors. Finally, the iron oxide-based nanomagnet also represents a very promising tool in particle/cell interfacing in controlling cellular functionalities, such as adhesion, proliferation, differentiation, and cell patterning, in stem cell therapy and tissue engineering applications.